Transmission system



Oct. 16, 1923. 1,470,965

G. W. ELMEN TRANSMISSION SYSTEM Filed Aug. 2, 1918 //7ve/1/0/ Gusfaf 14 f/me/v.

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Application filed August a, rare. seem an.

To aZZw/iom it mag concern.

Be it known that I, GUSTAF W. ELMEN, a citizen of the United States, lieonia, in the county of Bergen, State of New Jersey, have invented certain new and useful improvements inlransmission Systems, of whichthe following is a full, clear, concise, and exact description.

lhi s invention relates to a transmission system and has particular reference to telephone and similar systems.

An object of the invention is to provide an eliicient. magnetic repeater.

Another object is to provide an efiici'ent magnetic amplifier.

A further object is to provide an efiicient magnetic system from which hysteresis is absent.

A further object is to provide a magnetic system in which small changes in applied current will produce large changes in the permeability of the system, and consequently resultin large amplification powers.

The invention comprises a magnetic structure in which is established a magnetic field of a certain normal value. A high frequency alternating current winding is applied to the magnetic structure and by varying the value of this high frequency current it is found that a value is reached at'which any change in the flux normally set up in the structure will take place in accordance with a magnetization curve from which the usual hysteresis loop is absent. To provide means for changing the value of the normal flux set up in the structure, a variable flux of a frequency relatively low with respect to the high frequency, above mentioned, is impressed on the core. Such fluxes ma produced by voice currents on a telep one or other similar line which has a suitable winding associated with the magnetic structure. The normal flux in the magnetic structure may be produced by a winding having therein a battery and a transformer,

which latter is connected to a suitable re-' ceiver whereby the flux changes in the magnetic system may be noted.

It has also been observed that when the hysteresis loop has been eliminated in this manner, the magnetic system is very much more sensitive to changes in current, so that small changes in currents, low value currents, will-cause wide variations in the permeability of the system. In

residing atparticularly of accordance with this observation therefore, when small changes in low value currents occur, the flux in the system. varies correspondingly, but to amuch greater degree and sets up in the normal batte circuit, current changes of an amplified va nc which affect the receiver in the usual. manner and produce tones corresponding to those impressed. on the system but considerably amplified. The invention is illustrated in the drawing, in which Fig. 1 is a diagrammatic representation of thecircuits employed; and Fig. 2 is a diagram denoting the changes in magnetization and permeability.

As shown in the drawing, system comprises a core 1 of magnetic material which is shown in the form of a ring, although any other suitable form may be used. A winding 2 is applied to this core the magnetic and is connected to a circuit containing a battery 3 and a transformer 4, to one side of which is connected a suitable reecivin device 5. The strength of battery 3 1s predetermined so that the permeability normally produced is of some desired value. A winding 6 is likewise applied to the core 1 and is in circuit with a high frequency generator 7 and a capacity 8. The frequency of the currents in winding 6 is preferably several timesthe low frequency and preferably is above the ordinary range of voice currents used in a telephone line, for instance, it is of-the order of 10,000. The value of the current in winding 6 is increased and when a certain value is reached, depending upon the frequency used and the value of the flux set up by winding 2, it is found that any variation produced in the flux set up by winding 2 will vary in accordance with a magnetism curve, the increasing part of which coincides with the decreasing. part. In other words, given a normal flux of .a definite value applied to a core, and an alternating current of high frequency also ap-.

A winding 9 is also applied to the core 1 and is in circuit with atelephone line 10 which may be connected by a transformer 11 with a transmitter 12 of any suitable construction. The voice currents impressed upon circuit 10 and winding 9 by the action of transmitter 12 are of low value but cause very large variations in the flux set up in core 1, which large variations'are due to the fact that the previously mentioned relation has been established between the normal flux in the core due to winding 2 and the frequency and current value in winding 6.

As shown in Fig. 2, the curve 13 represents the variations in flux values in the core 1, with variations in magnetizing force, when the high frequency is applied to winding 6. Curve 14 represents the variation in permeability .values with changes in magnetizing force. It is to be noted that curve 13, which is the magnetization curve, shows no hysteresis loop and that curve 1 1 shows w1de variations in permeability for slight changes in magnetizing force particularly those of low value. The value of the current in bat tery 3 is preferably such that it will result in the permeability of the system being normally of the value desired which may be that represented by point 15 on curve 14; where the permeability curve has the greatest slope. v In the operation of the system, therefore, it will be observed that a frequency is applied to coil 6 of such value that the magnetization curve for the core 1 will show no hysteresisloop; the value of current in battery 3 is fixed to determine the normal value of the permeability in the magnetic system currents of relatively low frequency and of small value are applied to winding'9 and, because of the previously mentioned relation between the frequency in coil 6 and the flux set up by coil 2, cause large variations in the permeability which results in large flux changes, and correspondingl large variations in current, in the circuit of battery 3 which reproduce amplified voice currents in receiver 5.

What is claimed is: P

1. The method which comprises producing a magnetic flux in a magnetic medium, impressing a high frequency flux on said medium and varying the permeability of the magnetic medium for said first-mentioned flux in accordance with signals.

2. The method which comprises producing a magnetic flux in a magnetic medium, impressing a high frequency flux on said medium, varying the permeability of the magnetic medium for said first-mentioned flux in accordance with signals and transmitting to a distant station signals in audio frequency wave form derived from said variatlon.

3. The method which comprises producing a, definite magnetic flux in a magnetic medium, impressing a high frequency flux on said medium, and varying the permeability of the magnetic medium for said firstnamed flux in accordance with signals.

4. The method which comprises producing a magnetic .flux in a magnetic medium impressing a high frequency flux on sai medium, and varying the permeability of the magnetic medium for said first-mentioned flux in accordance with low frequency signaling current impressed on said medium.

5. A magnetic system comprising a core, an input coil and an output coil associated therewith, said coils being adapted to be traversed by currents of audio frequency, and a high frequency current coil associated therewith and adapted to superpose a high frequency magnetizing force on the system, said high frequency force havin a value above the range of essential voice equencies.

6. A magnetic system comprlsing a core, a low frequency coil and a receiving circuit associated therewith, and a high frequency current coil also associated therewith and adapted to superpose a high frequency magnetizing force on the system to prevent hysteresis loss, said high frequency force having a value above the range of essential voice frequencies;

7. A magnetic system comprising a core, means for producing and applying to said core a high frequency flux adapted to eliminate hysteresis 1n sald core, a receiving circuit associated with said core, means in said receiving circuit adapted to produce a flux in said core, and means for varying the permeability of said core forsaid last named flux to produce correspondingly amplified current variations in the receiver circuit.

8. A magnetic system'comprising a core, a high frequency flux adapted to eliminate I I o o u 0 hysteresls 1n sa1d core, a circuit associated with said core containing a source of energy, and a receiver adapted to set up a flux in said core, and means for varying the permeability of said core for said last named flux to produce correspondingly amplified current variations in the receiver circuit.

9. A magnetic system comprising a core, a high frequency flux adapted to eliminate hysteresis in said core, a receiving circuit associated with said core, means in said receiving circuit to establish a flux in said core, and means for varying the permeability of said core for said last named flux in accordance with low frequency signaling current impressed on said medium to produce correspondingly amplified current variations in the receiver circuit.

10. A magnetic system comprising a core, an input coil connected to a telephone line and associated with said core, a circuit containing a receiver and a source of energy associated with said core, and a high frequency current coil also associated with said core and adapted to superpose the high frequency magnetizing force on the system to prevent hysteresis oss therein.

11. A magnetic system comprising a core, an input coll connected to a telephone line and associated with said core, said input coil having means therein adapted to produce low frequency currents in said coil, a receiving circuit associated with said core,

means in said receiving circuit to produce in said core a flux of a definite value, a high frequency current coil also associated with said core and adapted to superpose a high frequency flux of a definite value on said system.

12. The method which comprises supply ing to a magnetic si aling device a current varying at an audib e frequency, supplying ultra-audio frequency current to said device and adjusting the intensity of said last named current to prevent said first named current from encountering hysteresis-loss in said device.

13. The method which comprises supplying to a magnetic amplifier a slowly varying current, supplying sa1d amplifier with ultraaudio frequency current and adjusting the intensity of said last named current until said first named current is prevented from Encountering hysteresis loss in said ampli- 14. A method which comprises superposing a constant flux, an ultra-audio frequency flux and a flux varying in accordance with the signal; and transmitting to a distant station in audio frequency wave form, currents derived from the last-mentioned flux.

In witness whereof, I hereunto subscribe my name this 29th day of July, A. D., 1918.

GUSTAF W. ELMEN. 

